No, the island has nothing but the players and plants. Also, on more detail with the abducting portal, it goes anywhere in time and space to snatch your character up, so you're character could be ask average Joe, and alien cat, it even just a robot, as long as it has s one means of communication with the others, etc, so they can have any technology from their time and species.

Edit: the reason there are no other creatures of intelligence is the alternate universes way of keep ping anything but the creatures it kidnaps from getting abilities.